Linux 4.8

This release adds support for using Transparent Huge Pages, bigger than 4K (in x86), in the page cache (used for backing filesystem data) automatically without user intervention. This release adds support for transparent huge pages in the page cache in tmpfs/shmem.
Support for eXpress Data Path, a high performance, programmable network data path has been added. XDP provides bare metal packet processing at the lowest point in the software stack. Use cases include pre-stack processing like filtering to do DOS mitigation, forwarding and load balancing, flow sampling and monitoring.
A new feature in XFS filesystem called reverse mapping allows XFS to track the owner of a specific block on disk precisely. This reverse mapping infrastructure is the building block of several upcoming features: reflink, copy-on-write data, deduplication, online metadata and data scrubbing, highly accurate bad sector/data loss reporting to users, and significantly improved reconstruction of damaged and corrupted filesystems.
A security feature has been ported from Grsecurity’s PAX_USERCOPY: stricter checking of memory copies with hardened usercopy. This feature kills entire classes of heap overflow exploits and similar kernel memory exposures. Performance impact is negligible.
Another feature taken from Grsecurity has been ported: GCC plugin support. GCC plugins are loadable compiler modules that can be used for runtime instrumentation and static analysis, allowing to analyse, change and add further code during compilation. Grsecurity uses these mechanisms to improve security.
This release implements RFC 5570: Common Architecture Label IPv6 Security Option (CALIPSO). Its goal is to set Multi-Level Secure (MLS) sensitivity labels on IPv6 packets using a hop-by-hop option. It is intended for use only within MLS networking environments that are both trusted and trustworthy
A new feature virtio-vsocks for easier guest/host communication has been added. This can be used to implement hypervisor services and guest agents (like qemu-guest-agent for example).
This release adds a new congestion control, TCP New Vegas is a major update to TCP-Vegas. Like Vegas, NV is a delay based congestion avoidance mechanism for TCP. Its filtering mechanism is similar: it uses the best measurement in a particular period to detect and measure congestion. It develop to coexist with modern networks where links bandwidths are 10 Gbps or higher, where the RTTs can be 10’s of microseconds.
In an attempt to modernize it, the kernel documentation will be converted to the Sphinx system, which uses reStructuredText as its markup language.
As always there were a lot of drivers improvements.
AMDGPU OverDrive support: the open source AMD Linux driver stack now supports overclocking.
Initial NVIDIA Pascal support: Nouveau has initial support for Pascal GPUs, but unfortunately no support for the consumer GeForce GTX 1060/1070/1080 graphics cards. Only the GP100 is supported so far until NVIDIA ends up releasing the signed firmware blobs for supporting the open source driver with the consumer GeForce GTX 1000 series hardware.
The HDMI CEC framework has been talked about for years and developed out-of-tree. HDMI CEC is short for the Consumer Electronics Control and allows HDMI-connected devices to be commanded and controlled by a user with a single remote control. With Linux 4.8 this framework is finally included.
Raspberry Pi 3 SoC: The Broadccom BCM2837 SoC is supported by the mainline Linux 4.8 kernel. There is also a variety of other ARM improvements.
Here is the full changelog.

This entry was posted on Saturday, October 8th, 2016 at 4:35 PM and is filed under linux.

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